The U.S. House voted Wednesday to end American assistance for the Saudi Arabia-led military campaign in Yemen.

The measure, which is now expected to go to the Senate, is a show of force for Democrats and a new challenge to the kingdom and its allies in the Trump administration.

Rep. Ro Khanna (D-Calif.), the resolution’s main sponsor, finally pushed his bill through on a 248-177 vote after Republicans repeatedly blocked it in the previous session. The measure invokes congressional authority over war and peace to require President Donald Trump to withdraw U.S. forces involved in fighting in Yemen, except those battling the local branch of al Qaeda.

It reiterates the message of a similar bill that passed the Senate late last year, and supporters hope the legislation will soon make it through the upper chamber again. Passage would force Trump to change course or justify a veto by explaining his ongoing support for a policy that has killed thousands of Yemenis and contributed to mass starvation there since the U.S. began helping the Saudi-led coalition in 2015.

“Today is historic,” Khanna said in a statement after the vote. “I’m encouraged by the direction people are pushing our party to take on foreign policy, promoting restraint and human rights and with the sense they want Congress to play a much larger role.”

The measure’s success in the House shows how much progress congressional critics of the war and activist groups have made in challenging the flow of American bombs, fuel and intelligence to Saudi Arabia, the United Arab Emirates and others battling Iran-backed rebels in Yemen.

Republican leadership stymied them in the House for years, shielding Trump from having to make a decision and protecting a strategy they view as a check on Tehran. They have used legislative maneuvers in three separate instances to keep Khanna’s bill off the House floor.

Skeptics of the war focused instead on winning over senators, tying concerns over Yemen to anger over the Saudi state’s role in the murder of journalist Jamal Khashoggi. With a Senate win under their belt, they pushed House Speaker Nancy Pelosi (D-Calif.) to promise an early vote once the new Democratic House came into session ― and on Wednesday, she made good.

All Democrats present in the chamber and 18 Republicans ultimately voted for the measure. More than 50 Democrats did, however, back a successful GOP-led amendment affirming the president’s right to share intelligence with foreign countries on vaguely defined national security grounds ― a signal that will reassure Riyadh and make the next Senate effort more complicated, as the body will now no longer be voting on the same language it considered back in December.

Pressure from Congress and growing global frustration with the Saudis have driven the warring parties to take negotiations more seriously. Even Trump felt compelled last year to rein in U.S. military support, officially ending the practice of refueling Saudi coalition planes midair to allow them to take longer bombing runs ― though he still has the right to change his mind, barring congressional action. A United Nations-brokered cease-fire has held since December with only a few exceptions.

But conditions are worsening for the tens of millions of Yemenis now dependent on some form of aid, and there’s been little progress on that front. Meanwhile, the Trump administration is continuing its saber-rattling on Iran while downplaying outrage over Khashoggi, and there’s growing evidence that American weapons given to the Saudi coalition have ended up in more dangerous hands.

Much of the GOP continues to argue that Yemen should be viewed primarily as a venue for confronting Iran, which has supplied the insurgent Houthi militia there. The resolution could represent a “green light” to the Houthis to continue taking arms from the Iranians and committing abuses like recruiting child soldiers, said Rep. Michael McCaul (R-Texas), the top Republican on the House Foreign Affairs Committee.

And in the Senate, the 53-member Republican majority is unlikely to welcome a companion bill to Khanna’s House resolution. A more targeted bipartisan package of sanctions on the Saudis over Yemen and Khashoggi hasn’t yet made it to the calendar of the Senate Foreign Relations Committee. That panel’s chair, Sen. Jim Risch (R-Idaho), opposed last December’s Yemen withdrawal bill.

Opponents of supporting the Saudi-led coalition ― who have formed an expanding network that includes several top conservative groups ― say they’re energized for the next fight.

“Congress realized #YemenCantWait,” Kate Kizer of the advocacy group Win Without War wrote on Twitter. “Onto the Senate!”

“Last year, an unprecedented 56 senators voted to end all support for this war, and that vote put much-needed pressure on Saudi Arabia,” Kate Gould of the Friends Committee on National Legislation wrote to HuffPost in an email. “Now, 51 of those senators are still serving in the Senate, and this legislation only needs 51 votes for passage.”